The universe of Harry Potter was created by J. K. Rowling beginning in 1990. For five years, she worked on not only the first book but also the outline of the entire series of seven books and the development of the world in which the stories occur. Rowling wanted her world to be consistent and detailed. She never suspected that so many people all over the world would be analyzing all that consistency and detail; she did the work for her own satisfaction.

Because of all this careful work on her part, the world Rowling created is rich beyond what can be included in the books themselves. She has written past histories of many of the characters and developed origins and back stories for many parts of her world. For example, she has written that the Death Eaters were originally called the Knights of Walpurgis. The Lexicon’s entry on this topic shows the richness of her work:

JKR made this comment during the Jeremy Paxman interview on the BBC, Thursday night, June 19, 2003, while looking at some of her notes on the books: “…here is the history of the Death Eaters and I don’t know that I’ll ever actually need it — but at some point — which were once called something different — they were called the Knights of Walpurgis. I don’t know if I’ll need it. But I like knowing it. I like to keep that sort of stuff on hand.”This is a play on “Walpurgis Night” — April 30th, named for Saint Walpurga (whose feast day is the next day, 1 May, and who is the protectress against witchcraft and sorcery). On Walpurgis Night, witches are supposed to meet in the Harz mountains, especially near the highest point. Incidentally, Walpurgis Night stands opposite the calendar from Halloween.

This depth of meaning and detail is found throughout the Harry Potter series. Casual readers of the novels will very likely miss most of it. The Lexicon is intended to help fans of the series understand and appreciate Rowling’s creative work at all these levels.

The ‘canon’

The Harry Potter Lexicon is an attempt to catalog in a user-friendly way all the information J .K .Rowling has given us about the world she has created, the universe of Harry Potter. For that purpose, a distinction is made between information which comes from the author herself and that which comes from other sources, whether officially licensed or not. Information which comes directly from Rowling is referred to as “the canon.”

The use of the term “canon” to represent the body of work by a particular author, excluding that which is added or derived by others, is not unique to the Harry Potter books. Aficionados of the Sherlock Holmes stories refer to Arthur Conan Doyle’s complete stories and novels as “the canon”. Holmes fans have been writing fan fiction and deconstructing the tiniest of canon details for decades. The same is true of fans of Tolkien’s Middle Earth saga. Potter fans are in good company indeed.

It would never occur to a Tolkien fan to include the animated Lord of the Rings film in their studies of that author’s work. No Holmes fan would argue a point about Dr. Watson’s skill as an M.D. based on lines from one of the plays or films that have featured the famous detective and his assistant. In the same way, the Lexicon makes a distinction between material which appears in the writings or words of the author and that which is derived from her work, such as the films or the video games. In order to make that distinction clear, it is important to state which sources are considered to be part of the canon and which are not.

The definition of canon is not agreed upon by all fans, however. A strict interpretation of canon insists that only information specifically stated in the books themselves qualifies, and (if you’re going to be extremely strict about it) only in the corrected Bloomsbury editions. By that definition, the discussion of the Knights of Walpurgis cited above would not be considered canon.

Most fans are willing to expand the definition of canon to include any information developed by Rowling, whether published in the books or stated in other sources. The Lexicon uses this expanded definition. Since Rowling herself treats the extensive backstory as part of her world, we do as well. Some of the back story is a bit difficult to categorize, of course. For example, can we say that it is canon that a dog-loving witch named Mopsy lives on the outskirts of Hogsmeade? In one draft of Harry Potter and the Goblet of Fire, Rowling had Sirius staying with Mopsy in his dog Animagus form. Since Mopsy never made it into the final version, is she canon? We’re not sure.

It is important to realize that there are still inconsistencies no matter how narrowly you define canon. Within the published books there are contradictions. Some of Rowling’s comments in interviews simply don’t fit with the world she’s described in the books. Some dates and other information on the Famous Wizard cards are just not logical. Fans like to assume that there is one true set of facts, and as a result they work very hard to rectify these inconsistencies.

For that reason, the Lexicon prioritizes canon sources. It is important for people trying to better understand the Harry Potter universe that they understand which canon sources are considered “more correct.” In a conflict of facts, higher canon trumps lower canon. However, in some cases later writings trump earlier writings simply because Rowling’s process of creation is evident and either changed her mind or fine-tuned the information. A good example of this are the departments of the Ministry of Magic. Several departments were mentioned offhand in earlier books which disappeared when she set down the official description of the Ministry in 2001 while working on book five.

Below you’ll find the list, with the most trustworthy canon sources listed first. The various canon sources on this list are linked to separate pages where they are described in more detail. The abbreviations following the sources are used throughout the Lexicon in endnotes.

Information which has come directly from JKR in either written or spoken form is considered canon. All other sources, including the film version from Warner Bros., are NOT considered official or canon, although some information from them is included in the Lexicon. The films are wonderful but they are considered to be very expensive fan fiction, not canon.

Here are what we at the Lexicon define as the three levels of canon:

Primary Canon

The Harry Potter novels

Bloomsbury editions, with corrections

Harry Potter and the Philosopher’s Stone (PS)
Harry Potter and the Chamber of Secrets (CS)
Harry Potter and the Prisoner of Azkaban (PA)
Harry Potter and the Goblet of Fire (GF)
Harry Potter and the Order of the Phoenix (OP)
Harry Potter and the Half-Blood Prince (HBP)
Harry Potter and the Deathly Hallows (DH)

Secondary Canon

Other Harry Potter books by Rowling

Quidditch Through The Ages (QA) (QA/i indicates the introductory material)
Fantastic Beasts And Where To Find Them (FB)
Scholastic and other English-language editions of the novels
The Tales of Beedle the Bard (TBB)
The Book of Spells (BoS)
The Book of Potions (BoP)

Other writings by Rowling

the original version of her website (jkrowling.com) (JKR) – no longer online, available here: http://web.archive.org/web/20110430090537/http://www.jkrowling.com/textonly/en/Pottermore (Pm) – writing attributed directly to Rowling, including the detailed information no longer found on the current version of the websiteThe Famous Wizard Cards (FW)The Daily Prophet newsletters (DP)The Black Family Tree (BFT) created by Rowling for the International Book Aid charity auction, Feb 21 2006The Harry Potter Prequel (Pre) – 800-word story written by Rowling to be auctioned for charity

Other canon sources – including some aspects of the theme parks, manuscripts Rowling created during the process of creating the world of Potter, etc.

Tertiary Canon

Other sources considered to be canon

other interviews where Rowling is not quoted exactly, but her comments reported

deductions made from canon, where such deductions are self-evident or virtually certain. (Any such assumptions are often challenged by fans or rejected outright. However, some amount of deduction is necessary and perfectly acceptable. In the Lexicon, we try to make sure we always indicate when we’re making these kinds of assumptions.)

Notes and details:

After the release of the fourth book, the world of Harry Potter expanded quite dramatically. Rowling sold the film rights of the series to Warner Bros. and also signed merchandising contracts with a number of companies. Rowling was called upon to create some “filler” for the development of the video games and other products. One result of this was the Famous Wizard cards. These cards appeared in the Electronic Arts games and were included in actual Chocolate Frog candy. They are now included on Pottermore.

The companies who used this information were not allowed by their contracts to indicate that their products included new Harry Potter information (author’s interview with Electronic Arts, 2007), so it can be a bit difficult to determine what is canon in, for example, a video game. However, Rowling announced on her website that she wrote the “original chocolate frog cards,” so we can say with certainty that those facts are canon.

Since all of this material was created by Rowling, the Lexicon includes it. However, numerous inconsistencies can be found in these sources, some of which are impossible to rectify. As Rowling makes corrections to the text and adds details on her website, some of these inconsistencies will be ironed out. The Lexicon will attempt to include the latest and most accurate information available.

However, in some cases there is no one “correct” fact. Since the Harry Potter universe doesn’t exist in objective reality, the facts only exist as Rowling states or writes them, and she may say different things. The Lexicon does try to give the “best guess,” but will also report conflicting facts as both being canon, which indeed they are.

A note about illustrations and artwork

As products were developed by these various companies, it became necessary to standardize the “vision” of the characters and settings of the Harry Potter universe. The resulting artwork appeared in a variety of places, from product packaging to coloring books. Rowling didn’t create that artwork, so it is not canon. The same is true for the illustrations in the Scholastic versions of the book or the cover art for any other version: since they didn’t come from Rowling herself, they are not canon. Rowling did create some illustrations for the books. Some of these illustrations appear on her website while others were shown during the “Harry Potter and Me” television special. Because they are directly from Rowling, they are considered to be canon, although they include details never mentioned in the books. Also, the artwork for the Pottermore website is directly controlled by Rowling and follows the books with extreme care (e.g. the students are shown wearing robes, not British school uniforms). These illustrations are considered to be tertiary canon.

Other non-canon sources for some information in the Lexicon:

Information from the filmed version of a book is referred to by adding /f to the abbreviation. Therefore the filmed version of Harry Potter and the Chamber of Secrets is noted as CS/f. Such information is not considered to be canon or official unless it is clear that it originated with JKR herself. Some of the details are mentioned in the Lexicon in the interest of completeness, however.

Information from the video game version of a book is referred to by adding /g to the abbreviation. Therefore the video game version of Harry Potter and the Chamber of Secrets is noted as CS/g. Such information is not considered to be canon or official unless it is clear that it originated with JKR herself. Some of the details are mentioned in the Lexicon in the interest of completeness, however.

The book The Bantam New College Latin & English Dictionary, revised and enlarged 1995 edition by John C. Traupman, has been used in the derivation of some words.

References are included from the New Shorter Oxford English Dictionary (NSOED) for the derivation of some words.

USDA, NRCS. 2005. The PLANTS Database, Version 3.5 http://plants.usda.gov. Data compiled from various sources by Mark W. Skinner. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.This database has been used to supply more information about various mundane plants.

Much of the information in the Muggle Encyclopedia was researched using Smith’s biography of JKR (cited as SS_JKRB):
Sean Smith, J. K. Rowling: A Biography, Michael O’Mara Books Limited, 2001).

Much of the speculative material, in the form of essays and some notes, is from fans who frequent the Harry Potter for Grown Ups group on Yahoo. The fan art is by a variety of talented artists, all of whom are listed on the pages on which their work appears.

The maps, which are actually fan art as well, were drawn mostly by Steve Vander Ark. A few were contributed by others, and these are carefully credited like any other fan art. Each map is carefully researched, and whenever possible, references from the canon are included below the map. However, they are not to be considered canon.

The day-by-day calendars are a “best guess” attempt to reconcile the events in each book with the actual calendar for the year in which those events take place. Where exact dates are not given or cannot be exactly extrapolated from stated dates, we have use the real world calendar to assume dates. These calendars are therefore partially non-canon, but portray the dates of events as close as is possible to deduce.